title: Problems in the conduct and analysis of "A comparative randomized study of three different IUDs in nulliparous Mexican women".
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007433:Intrauterine Device Expulsion / Q000009:adverse effects*; D007435:Intrauterine Devices, Copper / Q000009:adverse effects*; D008800:Mexico; D010146:Pain / Q000209:etiology; D010298:Parity; D011247:Pregnancy; D011275:Pregnancy, Unwanted; D016032:Randomized Controlled Trials as Topic; D014592:Uterine Hemorrhage / Q000209:etiology